CEO of Facebook, Mark Zuckerberg’s net worth has plunged at about $5 billion after his company shares slumped following the Cambridge Analytica scandal in which data of 50 million users was reportedly misused.

The company’s stock plummeted nearly 7 percent on Monday putting Facebook on track for their worst day in four years, Daily Mail reports.

Zuckerberg, who is currently the seventh richest person in the world, holds roughly 400 million shares, or 16 percent, in Facebook.

Following the drop, Zuckerberg is now worth an estimated $69.5 billion, according to Forbes.

His company is facing mounting calls to testify after reports emerged that the firm, which has links to President Donald Trump’s campaign, gained inappropriate access to data on 50 million Facebook users.

The reports have prompted a review by the company and expressions of concern by several US lawmakers who are demanding that Zuckerberg be grilled by the Senate Judiciary Committee.

The losses in shares on Monday would be among Facebook’s biggest daily fall, including a broader market pullback in February. In January, when Facebook announced changes to its newsfeed, which it said would hit user engagement in the near term, shares fell 4.5 percent in one day.

Facebook announced on Monday that it had hired a digital forensics firm to investigate the handling of data leaked to a consulting firm.